Conventional golf balls can be divided into two general classes: solid and wound. Solid golf balls include one-piece, two-piece (i.e., single layer core and single layer cover), and multi-layer (i.e., solid core of one or more layers and/or a cover of one or more layers) golf balls. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by a tensioned elastomeric material, and a cover.
Examples of golf ball materials range from rubber materials, such as balata, styrene butadiene, polybutadiene, or polyisoprene, to thermoplastic or thermoset resins such as ionomers, polyolefins, polyamides, polyesters, polyurethanes, polyureas and/or polyurethane/polyurea hybrids, and blends thereof. Typically, outer layers are formed about the spherical outer surface of an innermost golf ball layer via compression molding, casting, or injection molding.
From the perspective of a golf ball manufacturer, it is desirable to have materials exhibiting a wide range of properties, such as resilience, durability, spin, and “feel,” because this enables the manufacturer to make and sell golf balls suited to differing levels of ability and/or preferences. In this regard, playing characteristics of golf balls, such as spin, feel, CoR and compression can be tailored by varying the properties of the golf ball materials and/or adding additional golf ball layers such as at least one intermediate layer disposed between the cover and the core. Intermediate layers can be of solid construction, and have also been formed of a tensioned elastomeric winding. The difference in play characteristics resulting from these different types of constructions can be quite significant.
Ultimately, a golf ball must be able to withstand the great force and impact of a club face striking it. In this regard, tensile properties of golf ball materials such as the tensile strength and elongation are important considerations. Tensile properties indicate how the material will react to forces being applied in tension. In particular, tensile strength is a measure of the material's resistance to failure under an applied stress or load per unit area. Meanwhile, elongation measures the material's elasticity up to its breaking point under the load. That is, elongation measures the percentage (%) change in length before fracture. Such qualities are especially important in an outer golf ball layer which contacts the club face directly.
Therefore, there is a need for golf balls incorporating improved compositions which can exhibit excellent tensile strength and elongation without meanwhile sacrificing other important physical properties such as the specific gravity of a layer which is also an important property because it can effect characteristics of the golf ball such as Moment of Inertia (MOI). Such golf balls, which may meanwhile be produced cost effectively within existing manufacturing processes, would be particularly desirable and useful. The current golf balls of the invention incorporating such layers and methods for making same address and solve these needs.